The invention relates to inertial gas-liquid separators for removing and coalescing liquid particles from a gas-liquid stream, including in engine crankcase ventilation separation applications.
Inertial gas-liquid separators are known in the prior art. Liquid particles are removed from a gas-liquid stream by accelerating the stream or aerosol to high velocities through holes or nozzles and directing same against an impactor having a smooth impervious impingement surface causing the accelerated gas-liquid stream to follow a sharp directional change, effecting the noted liquid separation. These types of inertial impactors are typically used as measurement devices to classify and determine concentration and size distribution of aerosol particles. In particle size measurement devices, the smooth impervious impingement surface provides a sharp cut-off size such that particles above the cut-off size are separated, and those below the cut-off size continue in the stream. Such inertial impactors have also been used in oil separation applications for blow-by gases from the crankcase of an internal combustion engine.
The present invention provides an inertial gas-liquid separator with improved overall separation efficiency, including for liquid particles smaller than the cut-off size of a smooth non-porous impactor impingement surface. In one aspect of the invention, a rough porous collection surface is used for impingement, causing liquid particle separation from the gas-liquid stream of smaller size liquid particles than a smooth non-porous impactor impingement surface and without the sharp cut-off size of the latter. Overall separation efficiency is improved because of the additional separation of liquid particles smaller than the cut-off size of a smooth non-porous impactor impingement surface.
In another aspect of the invention, an inertial gas-liquid separator is provided with a rough porous collection surface causing both liquid particle separation from the gas-liquid stream and collection of liquid particles within the collection surface. The rough porous collection surface has a cut-off size for particle separation which is not as sharp as that of a smooth non-porous impactor impingement surface but improves collection efficiency for particles smaller than the cut-off size as well as a reduction in cut-off size. The rough porous collection surface provides a coalescing medium such that liquid particles, once captured within the collection surface, will coalesce with other liquid particles in the collection surface, and such that the accelerated gas stream and resultant high velocity of gas at and within the collection surface creates drag forces sufficient to cause captured liquid to migrate to outer edges of the collection surface and shed off of the collector.
In further aspects of the invention, various structural housing combinations and geometries are provided, and are particularly well suited to engine crankcase ventilation separation applications, though other applications are possible.